Dear kushy,
I recommend to make an assembly from the parts, and save the assembly as a part if You need it. As I know you can copy features, bodies from one part to another, but the I prefer to make an assembly (and save it as a part).

Thanks.
What is spit line?when to use this?Please give me one example.

Click to expand...

With split line feature you can define individual area(s) on face. I am use when I need a separate area on face, but I don't want to extrude, or cut. You can simply use to set a different color than the material itself (eg.: You want to sign the product with a red painted dot ), or it has a great advance when You simulate force on face (easy click and select force area on face).

Thanks.
What is spit line?when to use this?Please give me one example.

Click to expand...

With split line feature you can define individual area(s) on face. I use when I need a separate area on face, but I don't want to extrude, or cut. You can simply use to set a different color than the material itself (eg.: You want to sign the product with a red painted dot ), or it has a great advance when You simulate force on face (easy click and select force area on face).

If you mean inserting a view of an auxiliary part into your drawing (to depict an optional config for example), the answer is yes. Personally when part drawing, I do recommend to always add a view of the part in context, within its main assembly.